The dollar's plunge in New York and elsewhere over the weekend spilled over into Tokyo on Aug. 11, sending the yen soaring and share prices plummeting broadly.
The 225-issue Nikkei average ended the day at 18,824.18 points, down 780.28, or 4 percent, from Aug. 8. It was the average's first fall to the 18,000 level in 3 1/2 months.
The dollar changed hands at 115.12-15 yen at 3 p.m., against 118.55-56 yen at 5 p.m. Aug. 8.
In New York on Aug. 8, the dollar fell to 114.25 yen at one point amid concern over steep falls in share and bond prices.
Traders also blamed the dollar's weakness on Japan's bloated trade surplus in the first half of this year.
In Tokyo trading, nonetheless, the dollar showed a degree of resilience to the downward pressure.
There were indications that the dollar's steep fall prompted import-oriented companies to build their long dollar positions to meet their future needs.
Constant monitoring of the Japan-U.S. trade imbalance is required to assess the future direction in the dollar's value, said Naohiko Nakajima, vice president of Bank of America.
Unless Japan's trade surplus continues bulging in the third quarter, there appears a good chance that a capital flow into U.S. securities will gather fresh momentum, helping shore up the dollar, Nakajima said.